The subject matter disclosed herein relates to turbine systems and, more particularly, to a premixer assembly for mixing air and fuel for combustion within a combustor assembly of a gas turbine engine.
The primary air polluting emissions usually produced by gas turbines burning conventional hydrocarbon fuels are oxides of nitrogen, carbon monoxide, and unburned hydrocarbons. It is well known in the art that oxidation of molecular nitrogen in air breathing engines is highly dependent upon the maximum hot gas temperature in the combustion system reaction zone. One method of controlling the temperature of the reaction zone of a heat engine combustor below the level at which thermal NOx is formed is to premix fuel and air to a lean mixture prior to combustion.
The efficiency of premixing of the fuel and air is an important factor in emissions levels. The length of the tubes used for mixing of the fuel and air is determined by the mixing efficiency. Although longer tubes produce better mixing, lengthening of the tube undesirably necessitates additional cost associated with manufacturing of the tube and increases the overall size of the combustor and the gas turbine engine.